Traumatic brain injury (TBI) in younger children results in more severe and persistent sequelae than TBI in older children, affecting emerging skills most. Yet, little is known regarding the effects of early TBI on the family or the factors that facilitate or hinder recovery among children in this age group. Research suggests that family and social factors play an important role in determining longer-term outcome following TBI in school-aged children. The current investigation uses a prospective cohort design to examine family adaptation following TBI in young children and the relationship between the social environment and child recovery over time. Children aged 3 to 6 with moderate to severe TBI will be compared to a matched group of children hospitalized for orthopedic injuries not involving the CNS. Children in both groups will be assessed shortly after the injury and at 6, 12, and 24 months post injury. Child outcomes of interest include emerging skills in the domains of language, social competence, and executive functions that are likely to have important implications for later functioning. Family outcomes include injury-related burden, caregiver and family functioning, and parent-child interactions. We hypothesize that families of young children with TEI will exhibit more burden and caregiver distress, poorer family functioning, and higher levels of directiveness and restrictiveness in interactions with their children than families of children with orthopedic injuries. Further, we hypothesize that both the pre-injury social environment and changes in the family brought about by the injury will be related to the child's recovery, and that these associations will be moderated by injury severity, such that the environment has a stronger influence among children with more severe TBI. We anticipate that certain aspects of the environment (e.g., maternal maintaining behaviors) will accelerate recovery, whereas others (e.g., maternal directiveness) will retard growth following TBI. Understanding the relevance of the environment to the child's recovery following TBI will allow us to develop interventions to improve outcomes.